[PATCH] Null check to prevent null-ptr-deref bug

From: Prince Kumar Maurya
Date: Sun May 28 2023 - 12:44:57 EST


sb_getblk(inode->i_sb, parent) return a null ptr and taking lock on that leads to the null-ptr-deref bug.

Signed-off-by: Prince Kumar Maurya <princekumarmaurya06@xxxxxxxxx>
---
fs/sysv/itree.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/sysv/itree.c b/fs/sysv/itree.c
index b22764fe669c..3a6b66e719fd 100644
--- a/fs/sysv/itree.c
+++ b/fs/sysv/itree.c
@@ -145,6 +145,8 @@ static int alloc_branch(struct inode *inode,
*/
parent = block_to_cpu(SYSV_SB(inode->i_sb), branch[n-1].key);
bh = sb_getblk(inode->i_sb, parent);
+ if (!bh)
+ break;
lock_buffer(bh);
memset(bh->b_data, 0, blocksize);
branch[n].bh = bh;
--
2.40.1